IMHO probably due to not all judges being in complete concurrence--
there may be one or two dissents---there may be total concurrence
with one or more judges choosing to submit their own version of
the basis of the decision---deciding on narrower grounds or broader grounds.
My guess--a decision before April 15th with Siga winning---.You never
know however--strange things happen in the courts---not the least
of which is the original Parsons decision!